A photocathode is an opto-electronic device that emits electrons when it is struck by photons of light. A photocathode typically is used in a vacuum tube with an anode structure, where the electrons emitted from the photocathode pass directly to the anode structure. Where the photocathode includes electron-multiplying devices, such as, for example, multichannel walls and dynodes on a microchannel plate of the photocathode, large numbers of electrons may be emitted in response to the relatively few number of electrons emitted by the photocathode. This can be useful in a number of applications.
Solar blind deep ultraviolet (UV) photodetectors have attracted a strong interest due to their broad potential applications in the field of solar observations, ultraviolet astronomy, military defense, automatization, short range communications, security, as well as environmental and biological research.
Microchannel plate-based, photon-counting detectors remain the dominant technology for UV applications. However, future space missions in astrophysics, solar physics, planetary physics, Earth observation, and other disciplines may benefit from a highly sensitive, solar blind, radiation-hard UV and Far-UV photodetectors with a large sensitive area for more accurate readings and applications. Currently, most UV photodetectors require cesiated photocathodes in sealed tube. But this results in the UV photodetectors having a low quantum efficiency. Thus, there currently is a need for more efficient UV and Far-UV photodetectors that are non-cesiated with a greater quantum efficiency.